Director Jackie Verrall said the industry, which runs between Hove and Lancing, was usually 'very buoyant' but, since the Covid pandemic, they have been struggling for business.
Jackie said: "We were mandated to close for two years and now that we are open again, we can’t find host families for whatever reason.
"Sadly, the work is coming back but we are now turning students away – that’s a shame for us, of course, but also for the town where students spend a lot of money.
"Other people like me have closed down and given up. They can't be bothered.”
Jackie said she has been asked to support foreign students based in Eastbourne and Bournemouth due to the country-wide shortages.
She added: “For some reason, something has changed in people's mentality and they don't want students.
"We generally have seen this right across the UK and I don't know why.
"Where have the host families gone? Why have they changed their mind?"
Jackie said it was becoming a 'huge issue', adding: "We've had to close three centres down. We are now down to two coaches [from six].
"Where we might have put three kids in a family, it's now four.
"Agents are getting so desperate. Other people doing it for years have given up, they say it's not worth the aggravation. Probably in a way it isn't which is a shame."
Jackie doesn't believe the lack of interest has been caused by people being concerned over the risk of Covid.
She added: "People have put a guess in that it's natural wastage. One is people are still working from home but, with the recession coming on, you would think we'd have plenty of host families.
"The host families we've got are really helpful but they've only got so many beds.
"We've put adverts in shops, on Facebook, in groups. Newsletter goes to about 300 people. I've asked host families. Offered a finders' fee. People do try. The host families are brilliant. They are loyal and really want to help but nothing is coming.
"It's one of life's great mysteries. Next year, it will all be different.
"This year it's disappointing. This is our third season not able to trade."
Jackie said that, a couple of years ago – in the heady pre-COVID days – the business used to welcome six coaches most weeks into the Brighton area, 'full of foreign students'.
They were set for a 'bumper year' in 2020 with more than 125 coaches booked in.
Instead, the business has lost more than half of its host families.
Jackie added: "I have to say I was stunned when we had our first coach in and it was a real job to place one coach – so what hope do I have with six?
"Students are a huge industry and never more so than in the local Brighton area with students spending money in shops; tourist attractions; buses and of course paying for accommodation.